1. Field of the Invention
The present invention relates generally to a metal processing technique, and more particularly to an improved point-welding clamp structure.
2. Description of the Related Art
In the field of metal processing, different metal pieces are generally connected with each other by means of welding. Point-welding technique is widely applied to various fields not only including industrial product manufacturing, but also daily implement manufacturing. For example, point-welding technique is often applied to car body repair for recovering or modifying the original configuration of the car body. FIG. 1 shows a conventional point-welding clamp 1 for fixing the metal pieces in their true relative positions to facilitate the successive welding operation.
In structure, the conventional point-welding clamp 1 includes a frame-like main body 2 and a connection plate 3. The main body 2 has an opening 4 on a first side. The connection plate 3 has a first end and a second end. The first end of the connection plate 3 extends out of the main body 2 through the opening 4. The second end of the connection plate 3 has a threaded rod 5 passing through a second side of the main body 2. A nut 6 is screwed on the threaded rod 5. A press bar 7 is fitted through a perforation 8 formed at the first end of the connection plate 3 in adjacency to the main body 2.
In use, an operator inserts two different metal pieces to be welded together between the main body 2 and the press bar 7 with the adjacent edges of the metal pieces in abutment with two sides of the connection plate 3. By means of the nut 6, the connection plate 3 can be driven and displaced to tightly clamp and locate the metal pieces between the main body 2 and the press bar 7. Under such circumstance, the operator can perform point-welding operation to the two metal pieces.
In practice, the different metal pieces often have unequal thickness. However, the gap between the main body 2 and the press bar 7 of the conventional point-welding clamp 1 is uniform. Therefore, when using the conventional point-welding clamp 1 to clamp and locate two different metal pieces with different thickness, the metal pieces can be hardly both securely clamped and located. As a result, the application range of the conventional point-welding clamp 1 is limited.